Electronic components found in various types of transmitters, receivers, computers, and other electronic devices emit or are susceptible to electromagnetic radiation. It is therefore desirable to shield circuit components to reduce undesirable electromagnetic interference (EMI) and/or susceptibility effects with the use of conductive shields that reflect or dissipate electromagnetic charges and fields. Such shields are generally grounded to allow electrical charges and fields to be dissipated without disrupting the operation of the electronic components enclosed within the shield.
Various types of shielding devices for electronic components have been proposed; however, these devices have not been entirely satisfactory for components mounted on printed circuit boards. Components mounted on printed circuit boards are frequently enclosed within a frame or packaging that supports the components being shielded. The frame surrounds the circuit board components and a cover may be provided for enclosing the printed circuit board components. Various problems exist in the connection of the cover to the frame for use and periodic removal of the cover for visual inspection of the printed circuit board and components enclosed by the shield. Mechanical attachment devices between the cover and frame are cumbersome and do not provide sufficient retention of the cover for shock and vibration applications.
A need has thus arisen for an electromagnetic shield for printed circuit boards which provides effective EMI shielding of components in which a cover and frame are easily and selectively interconnected without the need for fasteners such as screws and the like.